from haystack import indexesfrom .models import SKUclass SKUIndex(indexes.SearchIndex, indexes.Indexable):    """    SKU索引数据模型类    """    text = indexes.CharField(document=True, use_template=True)    def get_model(self):        """返回建立索引的模型类"""        return SKU    def index_queryset(self, using=None):        """返回要建立索引的数据查询集"""        return self.get_model().objects.filter(is_launched=True)